xReg: issues with xReg (was discovery)

[duglin]

These might still apply to xReg - need to check:

WIP

https://github.com/cloudevents/spec/blob/master/discovery.md#get-services

• Any Service previously returned to a client that does not appear in this result can be assumed to be no longer available. I think this needs to be limited to just unfiltered queries since a missing entry from a filtered set could mean that it was deleted or that the filtered field changed.
• Discovery endpoints MUST support filtering with the following attributes and MUST reject any unsupported filters. we should probably say what the HTTP response code is.
• is Epoch allowed to be a negative int?
• "name" must be non-empty string
• typo: dataschama

Moved from: cloudevents/spec#863

[duglin]

I think we can close this one now.

• first bullet we have There is no guarantee that a future GET to the COLLECTIONsurl will return the exact same collection since the contents of the Registry might have changed, add something like: The specification makes no statement as to whether a subsequent GET missing an entity means that it's been deleted or not.
• second bullet will eventually be covered when we define what our errors look like: How prescriptive should we be about which HTTP error codes to return? #100